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MARTIAL DIMOCK, OF NEWARK, NEW JERSEY, ASSIGNOR TO SAM- UEL S. BARNABY AND DAVID MILLARD.

Letters Patent No. 95,666, lated October 12, 1869.

APPARATUS FOR EXHIBITING' PHOTOGRAPHS,I

The Schedule referred to in these Letters Patent and making part of the lsame.

To all whom it may concern:

Be it known that I, MARTIAL Dmook, of the city of Newark, in the countyiof- Essex, and State of .New Jersey, 11a-ve made certain. Improvements in the Mechanism of the Apparatus for Preserving and Exhibiting Photograpli-Pictures, for which a patent was `issued to Charles Robinson, on the 11th day of April, 1865, and a second patent, October 17, of the same year; and do declare the following, taken iu connection with the accompanying drawings, to be a full and exact description ofthe same.

The nature of thel improvement consists in a connection of the cylinders in a way to insure simultaneous movement, without dependence upon the mounting-band, and in a seliladjustment of theinequality of the winding-increase of size of one cylinder, and decrease of diameter in the other, as the mounting-band passes from the one to the other, and which, at the same time preserves an even tension upon the mounting-band.

As the improvement is' upon that which is already patented, an extended description of parts is not neces sary. A

'- In the drawings of the patent issued in April, 1865,

may be seen, on the front of the enclosing-case, over the two knobs for turning the cylinders, the notices turn to the right, turn to the left, which, not being always heeded, have manifested the defects which our improvement perfectly prevents ever again recurrinv.

nhe loosening the band, and consequent tearing the mounting, or-deiacing the picture that almost inevitably occurred from turning either knob the wrong way, are rendered impossible by the gearing a a a, Figures 1 and 2, in the drawings; one wheelbeing upon the 'shaft of. cylinder I), and one upon that of cylinder c, with an intermediate between them, it matters not which knob is turned, nor which way itis turned, the band is passed from one cylinder to the other.

Upon the shaft of the cylinder c is placed the spiral spring d, one end of which being attached to the shaft., andthe other to the interior of the cylinder, the cyl- -inder being loose upon the shaft, has the effect of keeping an even tension upon the mounting-band, as the speed of the two cylinders is varied bythe increase of diameter in one, by the band being wound upon ii, and the decrease of the diameter of the other, as thc band is unwound therefrom.

lhe springs c assist in steadying the motion and holding the mounting-band in its position while the pictures are being viewed.

As the original patents are now solely owned by the assignees of this patent, no disclaimers relating thereto are needed.

NVhat is claimed, and desired t'o be secured as needful to make the invention available for profit, is-' The connection of the cylinders b and @substantially in the manner and for the purpose herein above set forth, and the tension-spring in the cylinder, when used in combination therewith.

MARTIAL DIMOCK.

\Vitnesses W. M. GooDrNe, EDWARD OoLLvnn. 

